double myPow(double x, int n)
{
    return n > 0 ? pow(x, n) : 1.0 / pow(x, -(long long)n);
}
double pow(double x, long long n)
{
    if (n == 0) return 1.0;
    double tmp = pow(x, n / 2);
    return n % 2 == 0 ? tmp * tmp : tmp * tmp * x;
}
